Malicious software, also called malware, refers to programming (code, scripts, active content, and other software) designed to disrupt or deny operation, gather information to violate privacy or exploitation, gain unauthorized access to system resources, and enable other abusive behavior. The expression is a general term used by computer professionals to mean a variety of forms of hostile, intrusive, or annoying software or program code.
Malware includes various software including computer viruses, worms, Trojan horses, spyware, dishonest adware, scareware, crimeware, rootkits, and other malicious and unwanted software or program, and is considered to be malware based on the perceived intent of the creator rather than any particular features. In legal terms, malware is sometimes termed as a “computer contaminant,” for example in the legal codes of U.S. states such as California.